Field
The embodiments discussed herein relate to computed tomography imaging systems.
Relevant Technology
Cone beam (CB) computed tomography (CT) involves the generation of volumetric image reconstruction of the internal structure of an object by collecting multiple projection images (“projections”) in a single scan operation. Computed tomography is widely used in the medical field to view the internal structure of selected portions of the human body. Computed tomography is also used in the industrial and security fields to perform nondestructive inspection and to detect contraband and weapons in security screening.
Generally, multiple two-dimensional projections are made of an object. These two-dimensional projections are typically created by transmitting radiation from multiple positions through the object. The object absorbs some of the radiation based on the size and density of the object's internal structure. The unabsorbed radiation is collected by an imaging device, or imager, which typically includes an array of detectors. The two-dimensional projections may be generated using information about the relative attenuation of the radiation as collected by the imager. The collected two-dimensional projections may be used to generate a three-dimensional representation of the object using various tomographic reconstruction methods.
The quality of the three-dimensional representation of the object may depend on a number of factors. For example, the intensity of the radiation transmitted from the point source will affect the signal-to-noise ratio of the collected radiation. Furthermore, conventional algorithms for reconstructing the three-dimensional representation from the multiple two-dimensional projections may introduce inaccuracies to the representation, which are generally described as artifacts.
Conventionally, x-ray radiation is used in generating the two-dimensional projections of the object. Often, but not always, the x-rays are produced by an x-ray device rotating around the object. Generally, the x-ray devices contain a cathode that emits a flow of electrons that impinge material of a particular composition located at a target surface of an anode. As the electrons impinge the anode, x-rays and heat are produced. A beam of the resulting x-rays is directed toward the object and the imager. Increasing the flow of electrons that impinge the anode may increase the intensity of the resulting x-ray beam, but the heat produced is also increased.
Preferably, the temperature of the target surface, the anode, and/or other portions of the x-ray device are kept within a desired range to reduce the likelihood of heat-induced failure. The anode is often implemented as a disk spinning at high speeds. Generally, disk anodes absorb more heat without failure than stationary anodes. However, even with a disk anode, heat generated at the anode may act to limit the intensity of the x-ray beam.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.